Building the USS Missouri – Part 1

See also Parts 2 and 3

In 2011 I re-entered the Meccano world after a break of about 40 years by joining the South West Meccano Club. This resulted from an enlightening discussion at a local model engineering exhibition which had a Meccano stand. The next few years were spent collecting and restoring old Meccano as my childhood collection paled into insignificance when I saw what could be built by proficient builders in this club and other clubs. I was encouraged to build something by other club members rather than just restore stuff, so I obliged by building a braiding machine from a picture I found in an old Meccano Magazine (more my wife’s choice than mine!). This didn’t go so well even with attempted improvements. So in late 2012 I decided my next attempt, my first major ‘own design model’ ought to be something better.

The back story of my USS Missouri - plus a detailed description and photos of the finished model – has been published in Constructor Quarterly issue 127. However, this did not go into the build detail, nor tell of the interesting problems encountered along the way.  See the  Constructor Quarterly website.

This illustrated build blog will – I hope – be of interest to others. Pictures weren’t taken every step of the way so there are gaps in the build stages. It will actually serve as a reminder for me of how I built it while still relatively fresh in my mind, as I don’t intend to dismantle it, but it will need maintenance by me or someone else in the future.

Why the Missouri?

I wanted to build something different and visually impressive. I also wanted it to have lots of functionality, as in my professional life mechanisms were sort of a speciality of mine. There have been many ships displayed at exhibitions, the vast majority of which were ‘waterline’ models. Building a full hull ship would present a challenge and would look good if minimally supported, thus showing off the full hull to its best. And if it were to be a ship, then a battleship offered many opportunities for functionality in the turrets and radars, in addition to the usual anchors, propellers and rudders. OK then - a battleship - but which one?

I chose the USS Missouri in particular for many reasons. Apart from looking the business, it has a famous history. From a practical point of view, as it still exists there is plenty of info on the internet about it, with many pictures, and the USS Missouri memorial website at the time of planning included .pdf’s of the GA ‘as built in 1943’ blueprints.

Original side view from the blueprints

These proved invaluable as you will later see. Also, the ship has parallel sides which I suspected would make building a little easier. This old aerial photo shows the USS Missouri (upper of the two) in port, where the straight sides are apparent. Compare this to the Bismarck class which had fully curved sides, or the Yamato class which had an awkward stern profile.

Bismarck class battleship
Yamato class battleship

Scale

Having settled on the Missouri, the scale needed deciding. I wanted the barrels to recoil, thus the turrets had to be large enough to accommodate the mechanisms, so this principally drove the 100th scale. Obviously, a 100th scale makes the scale calculations easy, and as it happens, the deck width at this scale is just over 12.5 inches, and I thought “that’s handy”! In the end, the apparent advantage of this width never materialised as no single component at deck level spans the width, therefore the 12.5 inches didn’t matter. The downside is that even at 100th scale, the finished model is just under 9 feet long. The photo was taken at The London Model Engineering Exhibition at Alexander Palace in January 2020.

An appreciation of the scale

Before assembling a single nut and bolt……….

Planning started with establishing what I wanted as key features, to ensure they could be accommodated right from the start. The basic attributes - and checks during build that they can be achieved - is an aspect of ‘Requirements Engineering’ useful for a complex build to avoid disappointment. The top level requirements were:

  • To be self-supporting
  • Transportable
  • Accessible to build
  • Main turrets to have triple functions
  • Ancillary functions of 5” gun turrets, radars, anchors, propellers, rudders
  • Function reliably at meetings and exhibitions

This last one of reliability is because of the many times I’d heard “it worked fine at home just before I brought it, so why won’t it work now?” The following extensive (sorry) illustrated build write-up reveals how these were achieved.

The USS Memorial website GA blueprints included some of the key dimensions of the ship, and had all the frame stations marked which were at a pitch of 4ft. Using the known dimensions the images were scaled up appropriately and printed. The next picture shows faint marks of 15 frame pitches superimposed under a blue box of exactly 1/100th scale. The first attempt at this resulted in incorrect and inconsistently scaled prints. It turned out that my printer software chose to override my carefully set scaling with its own ‘scale to fit’ setting which screwed things up. Un-ticking that option solved the problem.

Blueprint frame pitching
Hull cross sections

The blueprints also included hull cross sections, and plan views of all the deck levels. This, combined with the many old and new pictures on the internet provided enough imagery to work from.

Being self-supporting in this instance (i.e. not using a wooden cradle or having anything other than Meccano inside to keep it from deflecting) was a structural challenge, the first step of which was knowing what was to be supported. At 9ft long it was clearly going to be heavy, so a weight estimate was needed. During collecting and restoration, I had weighed a sample of each Meccano part to understand what the floor loading would be when storing the collection in tall cabinets. I was concerned if I were to keep it in a bedroom of a modern house where materials were ‘value engineered’. Having this weights data gave me an appreciation of what the ship might finally weigh.

I had no way of transporting it in one piece, nor anywhere to build it downstairs (if built upstairs it would be impossible to get down!). The solution was to plan the construction as 4 sections which could be assembled/disassembled quickly. Building it in sections meant there would be joints along the hull, and the easiest type of quick disconnect joint is a pin joint. The ‘breaks’ for the hull joints had to miss the superstructure, and be accessible for pin insertion. The ‘break lines’ were chosen to be just behind the back end of the forward and aft turrets, as these would not interfere with the workings of the turrets, and apportioned the section sizes reasonably well. The location of the pin joints can be seen on my initial sketches.

To eliminate any induced twist in the model when being carried or displayed on an uneven surface, there could only be three support points under the hull. The hull profile lent itself to be one at the front and two at the rear. The spacing of the rear two was a function of structural needs and hull shape – more on this later.

A low cross section through the hull

Using the weights data as a guide, I crudely estimated the ‘worst case’ weight of each of the 4 sections and sketched a diagram to approximate where the CG of each section would be. These estimates were:

  • 20kg Bow section
  • 25kg Centre section
  • 20kg Stern section
  • 25kg Superstructure section
Guestimated CG locations for each section

This CG information is the start of designing the central structure which will be described in part 2.

Continued in Parts 2 and 3